Bleaching process.



CAIEQN OF TEXTILES & FIBERS,

UNITED STATEfi PATENT @FFIOE.

HAN'NS R. ANDERS, OF PERTH AMBOY, NEW JERSEY, ASSIGNOR TO THE ROESSLER & IIASSLACHER CHEMICAL C0,, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

BLEACI-IING PROCESS.

No Drawing.

To all whom it may concern:

Be it known that I, HANNS R. ANDERs, a subject of the Emperor of Austria, residing at Perth Amboy, 1n the county of Middlesex and State of New Jersey, have invented certain new and useful Improvements in Bleaching Processes, of which the following is a specification.

This invention relates to processes of bleaching and relates particularly to the bleaching of industrial fibers, including vegetable fibers, as for instance grasses, leaves, stalks and wood by means of hydrogen peroxid solutions.

It is well known that fibers, especially vegetable fibers like grasses, leaves and stalks, present considerable difficulty to satisfactory treatment by the present bleaching processes because their strength is usually aifected by the various steps of treatment or they are otherwise injuriously affected by the combined effect of such steps on the fibers. I have discovered however a new process of treating such vegetable fibers or the fabrics made of the same by which goods of a satisfactory shade and of perfect strength of fiber may be obtained. A further improvement resulting from the practice of my process is that the material treated may be finished in a much shorter time than heretofore because the bath can be applied at a higher temperature without harmful influence upon the strength and appearance of the material.

Formerly alkaline carbonates. phosphates and silicates, as well as caustic alkalis, were used in the first step of the bleaching process, i. e. the step wherein the material, for instance, straw, was treated with alkaline solutions at a temperature not exceeding 200 F., in order to wet-out the material and remove part of the coloring matters. These alkalis were also used for making the peroxid bleach bath alkaline.

In my new process the above-mentioned alkalis are substituted by suitable lime compounds, of which the most preferable is calcium hydroxid in solution.

Specification of Letters Patent.

Patented Jan. 1, 1918.

After having soaked the materials in milk of l1me at a temperature from normal to not exceeding 200 F., depending. upon the nature of the fiber, to wet-out the coloring matter, I bring them into the bleaching bath WhlCh I prefer to prepare as follows.

Ten gallons of a 25% vol. H O solution are added to 80 gallons of water, previously heated in the mixing tank to a somewhat higher temperature than is required in the application of the bath to the material to be treated. In this instance the temperature may vary from about normal to not exceeding say 200 F. according to the nature of the material undergoing treatment. To the diluted solution thus obtained lime water is added until the bath is brought to the desired degree of alkalinity depending upon the material acted upon and the degree of bleaching desired to be obtained. The cold additions to the hot water, i. e. the added H O solution and the lime water, lower the temperature of the bath to a degree just suitable for its application.

It is of course understood that I may substitute the hydrogen peroxid solution mentioned in the above example, by a solution containing hydrogen peroxid obtained from any suitable source, as for instance by that obtained from a peroxid or other percompound yielding hydrogen peroxid when dissolved in water.

It is furthermore understood that the bleaching process depends somewhat upon the material to be treated and that the details of the process may be slightly modified carrying active oxygen rendered alkaline by means of an hydroxid of an alkali earth metal.

2. The process of bleaching industrial fibers and fibrous materials, consisting in preparing the fibers by Wetting-out the same, at an elevated temperature, in lime Water and. then bleaching them in a bath of a substance carrying active oxygen rendered alkaline by means of calcium hydroxid. m

In testimony whereof I have signed this specification.

HANNS R. ANDERS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

